Device for freeze drying and synthetic resin impregnation when necessary of small biological objects for electron microscopic examination

Abstract

A tray for holding a biological specimen and a submersible container for freeze-drying the specimen are disclosed. A heating element to melt a synthetic resin for embedding the specimen is also disclosed.

What is claimed is: 
     
       1. A device for freeze drying and synthetic resin impregnation of biological specimens which comprises a Dewar flask for holding a cooling liquid, a sealable container, support means for supporting said container in said Dewar flask below the liquid for cooling said container, valve means for connecting said container to a source of reduced pressure for evacuating said container, a sample tray having at least one recess for receiving a biological specimen, means for supporting said tray within said container spaced from the container interior and heating means for warming said tray. 
     
     
       2. Device according to claim 1, characterized in that the submersible sealable container comprises two separable components, a gasket (17) and can be pressed together by means a threaded ring (33, 33a), and which are secured against rotation relative to one another. 
     
     
       3. Device according to claim 2, characterized in that the threaded ring (33a) is supported through a pressure roller bearing (35b) on one of the sealable container components (18b) and the gasket (17b). 
     
     
       4. Device according to claim 2, characterized in that the gasket (17b) consists of soft metal, in which one or more gripping points (34) can be impressed. 
     
     
       5. Device according to one of the claims 1, 2, 3 or 4, characterized in that the sealable container contains a molecular sieve. 
     
     
       6. Device according to one of the claims 1, 2, 3, or 4, characterized in that the sample tray (8b) is connected exchangeably with the submersible device by means of a rapid connector. 
     
     
       7. Device according to claim 6, characterized in that the rapid connector is a contact plug (30a, b) through which the sample tray (8b) can be heated electrically and can be adjusted in its temperature. 
     
     
       8. Device according to claim 7, characterized in that the holder of the contact plug (30a, b) consists of a poor heat-conducting material. 
     
     
       9. Device according to one of the claims 1, 2, 3, or 4, characterized in that the recess or recesses of the sample tray (8a, b), is or are also formed to accept a solidified synthetic resin monomer (36). 
     
     
       10. Device according to one of the claims 1, 2, 3, or 4, characterized in that the sample tray (8c, d) consists of two components, wherein one component (8d) is connected with the upper part (18b) of the submersible device through a connecting link (36) with poor heat transfer properties, and contains a temperature sensor and a heating element, while the second component (8c) is in good heat contact with the rigidly fastened part (8d) through a flat surface, and is connected with it in an easily separable manner. 
     
     
       11. Device according to claim 10, characterized in that the separable component (8c) of the sample tray is subject to variable contact pressure by an adjustable assembly element. 
     
     
       12. Device according to one of the claims 1, 2, 3, or 4, characterized in that a device is provided in the Dewar flask (20) for monitoring the filling level of cryogen. 
     
     
       13. Device according to one of the claims 1, 2, 3, or 4, characterized in that a semi- or fully-automatic program control is provided for the temperature of the object as a function of time.